Wildfire occurrence of pine forests in Central Siberia in a changing climate
I. A. Petrov1,2,3, A. S. Shushpanov1,3,4, A. S. Golyukov1,2,3, M. L. Dvinskaya1,3, V. I. Kharuk1,2,3
1V. N. Sukachev Institute of Forest SB RAS, Krasnoyarsk, Russia
2Siberian Federal University, Krasnoyarsk, Russia
3Tomsk State University, Tomsk State University
4Reshetnev Siberian State University of Science and Technology, Krasnoyarsk, Russia
Keywords: wildfires, burnt areas, wildfire occurrence in pine stands, productivity on burnt areas, GPP and NPP on burnt areas, climate and wildfires, remote sensing and wildfires
Abstract
Climate changes entails an increase in the forests burning throughout the whole boreal zone. We have studied the long-term dynamics of fire rate and post-fire recovery of vegetation cover productivity in the pine forests of Central Siberia, and analyzed the dependences of the fire frequency and the burnt areas on climatic variables. Methodically, the work is based on a combined analysis of data from ground surveys, remote sensing (spectroradiometric and gravimetric surveys by Terra / MODIS and GRACE satellites), and coupled analysis of dendroecological data and environmental and climatic variables. The main impact on the fire frequency and burnt areas is due to the moistening conditions (total precipitation, soil moisture, aridity index scPDSI) in the period preceding the fire. The correlations of combustibility parameters with air temperature are lower than with humidification conditions. It is shown that soil moisture gravimetry data can be used in assessing the risk of forest fires. A decrease of fire Return intervals from 33 years to 20-25 years in the period from the 18th to the 20th century was revealed. In the second decade of the 21st century, both catastrophic (more than 1 million ha) forest fires and a significant increase in flammability were observed: the number of fires and the area of burnt areas increased, respectively, by 3.5 and 3.0 times. A high level of correlation has been determined between the growth index of pine trees and the vegetation cover productivity indices (gross (GPP) and net (NPP) productivity) generated from remote sensing data. The result obtained indicates the applicability of the indices in the studies of the forest stands productivity. Significant trends in flammability in the 21st century, both in terms of the frequency of fires and the areas covered by fire, have not been identified. The productivity of the vegetative cover on burnt areas, as well as the value of the index of radial increment of pine trees, quickly (within ~ a decade) recovers to pre-fire values, which indicates that northern pine forests retain their carbon-storing function under conditions of climate change and increased fire rate.
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